function DefindMap(){
	 this.data = new Array();
	 
	 this.set = function(key,value){
	  this.data[key] = value;
	 };
	
	 this.get = function(key){
	  return this.data[key];
	 };
	
	 this.remove = function(key){
	  this.data[key] = null;
	 };
	 
	 this.isEmpty = function(){
	  return this.data.length == 0;
	 };
	
	 this.size = function(){
	  return this.data.length;
	 };
}